Avalanche Forecast

Archived

Dec 4th, 2023–Dec 5th, 2023

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Regions

Kananaskis, Bow Valley, Highwood Pass, North 40, Spray - KLakes.

Warm temperature and snow will quickly change the avalanche hazard. Caution for ice climbers.

Confidence

Low

Avalanche Summary

No new avalanches have been observed. Expect to see some activity with the change in weather.

Snowpack Summary

A major change in the weather will happen on Tuesday and Wednesday. Approach all terrain with caution.

Expect up to 10cm of snow with winds on Tuesday and another 10cm on Wednesday which has the potential to create a reactive wind slab at tree line and in the alpine. Warm temperatures and rain also has the potential to make any slabs that are already present in lee features and cross loaded gullies to be more sensitive to triggering. Any new or old slabs will now be sitting on an extremely weak base comprised of facets, depth hoar, crusts and surface hoar.

Weather Summary

Expect temperatures to rise on Tuesday with freezing levels going as high as 2600m. One can expect 5-10cm of snow by late evening but with low confidence in where the rain/snow line will be in relation to treeline elevation. Winds are forecast to be 50-60km/h from the SW.

Wednesday

Expect another 5-10cm of snow with slightly cooler temperatures and a freezing level of 2100m. Winds are expected to diminish to 20-30km/h from the SW.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Pay attention to the wind, once it starts to blow fresh sensitive wind slabs are likely to form.
Avoid terrain traps where the consequence of any avalanche could be serious.
Approach lee and cross-loaded slopes with caution.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.